It is known for the shaft of such a tool to be held in a central receiving opening of an annular, self-contained part, most often embodied as a tube part, of a tool holder by means of a press fit. This tube part forms the end toward the tool of a tool holder of otherwise conventional design.
This part or tube part of the tool holder can be widened by heating so far in the radial direction that the cold shaft of the tool can be thrust into the tube part or pulled out of it. As soon as the tube part has cooled down again, a pressure bond forms between it and the shaft of the tool, by means of which pressure bond the tool is reliably fixed in the tool holder (shrink-fit technology; see for example EP 1 353 768 B1).
Alternatively, chucking can also be done hydraulically. For that purpose, inside the aforementioned tube part of the tool holder, a hydraulic clamping device is provided, which upon imposition of hydraulic pressure reduces its inside diameter embracing the tool shaft and thus chucks the tool shaft by frictional engagement.
As a third alternative, there is the possibility of bringing about the pressure required for secure chucking of the tool shaft by frictional engagement purely mechanically as well, for instance by means of spring collet chuck per DIN ISO 15488 or EP 1 291 103, or roller jaw chucks per DE 35 172 46.
Collet chucks of the type described have proved themselves very well in practice.
In general in collet chucks of the described type, there is the problem that under unfavorable circumstances, because of reaction forces that originate at the cutting edges of the tool that are exposed to rapidly alternating stresses, vibration is induced, which not infrequently is in or near the resonant range. This vibration can make itself felt so markedly in the complete system comprising the tool, collet chuck and machine tool, that the cutting speed and/or the feeding speed have to be reduced, which impairs the performance of the concrete system and is therefore unwanted.
It is known that the tendency to vibration of such a complete system can be favorably affected in some cases by “softer” chucking of the tool.
It is now the object of the present invention to disclose a means which makes chucking the tool in a way that especially favorably affects the vibration behavior of the tool, without making compromises in the machining precision.